During the installation you can accept all of the defaults, do not change 'Use Git and optional Unix tools from the Windows Command Prompt' option for Git and SSH operations, shown below:

After the installation is completed, to verify that Git is correctly configured run:

git --version

If the version of Git is displayed, means Git was installed successfully and has been add to path env variable.

On your machine, first you will need to navigate to the project folder using git bash. When you get there you do:

git init

which initiates a new git repository in that directory.

When you've done that, you need to register that new repo with a remote (where you'll upload -- push -- your files to), which in this case will be github. You'll get the correct URL from your repo on GitHub.